What is the technique for quantifying reflected color in architectural glass?

In the two glass window panes above you can probably notice a difference in the transmission color between the two. The one on the left appears greener while the one on the right appears bluer. There is another difference; the two samples have a difference in reflectance as well. The sample on the left has a reddish/purple reflectance color whereas the one on the right has a slightly bluish reflectance color.

Is it possible to quantify this difference in reflectance color on a transparent sample such as these architectural glass panels? Yes, HunterLab instruments not only allow for the measurement of transmission color, but can also measure the color of the reflection from the glass (or specular reflectance).

To measure the specular reflectance of the sample, a sphere instrument is needed that has been standardized in reflectance specular-included mode. Samples are placed at the reflectance port backed with a light trap so that only the specular reflectance of the sample is measured.

Architectural glass is most commonly used as a building material. Manufacturers are successfully able to use HunterLab instruments to measure architectural glass and insure uniformity among building projects. Architectural glass is usually treated with chemicals to strengthen the glass or to improve insulation and more. This measurement method is also applicable to those who manufacture coated films that are used for similar purposes.